1. Field of the Invention
The present invention relates to a negative photoresist composition and a method of manufacturing an array substrate using the negative photoresist composition. More particularly, the present invention relates to a negative photoresist composition which can be utilized for an organic insulation layer of a liquid crystal display (“LCD”) apparatus and a method of manufacturing an array substrate using the negative photoresist composition.
2. Description of the Related Art
A conventional LCD apparatus includes an array substrate having a thin-film transistor (“TFT”) which is a switching element for operating a pixel of a display panel of the LCD apparatus. The TFT is protected by a passivation layer. An organic insulation layer is formed on the passivation layer to planarize a substrate, to thereby improve resistive-capacitive (“RC”) delay and an aperture ratio.
Compositions which are used for the organic insulation layer include a positive photoresist composition and a negative photoresist composition. The positive photoresist composition includes a 1,2-quinone diazide compound as a photosensitizer. However, the 1,2-quinone diazide compound is heated when forming an organic insulation layer so that the 1,2-quinone diazide compound is of a red color. Thus, the light transmittance of a pixel with respect to visible light is reduced.
The negative photoresist composition is not discolored like the positive photoresist composition, and has high photosensitivity compared to the positive photoresist composition. However, a developing solution easily causes swelling in the negative photoresist composition in a developing operation after an exposure operation has been performed. Thus, the resolution and adhesion between an organic insulation layer and a substrate is reduced. In order to solve the problems of the negative photoresist composition, solubility and the affinity of the organic insulation layer with respect to a developing solution have been reduced.
However, reducing the solubility and the affinity of the organic insulation layer with respect to a developing solution can cause problems, for example, in that detachability may be reduced, and residue may be formed. Thus, the display quality of the LCD apparatus may be reduced.